I am going to build a fence, planning to cast footings, and found an instruction text. According to it, you should dig 50 cm deep holes and fill them with 10 cm gravel and 10 cm ground insulation before you pour the concrete. The holes should be 50 cm in diameter. I have a few questions about this.
1. Ground insulation - is it polystyrene that you crumble into the hole...?
2. Why should the hole be 50 cm in diameter? Why isn't it enough with a hole just large enough for the pipe to go down?
3. 10 cm gravel and 10 cm ground insulation, that would mean 30 cm concrete. Is that enough?
Tips and advice for a footing caster and fence builder are greatly appreciated.
(Edit: Maybe this should have been under earthworks & foundation...)
1. Ground insulation - is it polystyrene that you crumble into the hole...?
2. Why should the hole be 50 cm in diameter? Why isn't it enough with a hole just large enough for the pipe to go down?
3. 10 cm gravel and 10 cm ground insulation, that would mean 30 cm concrete. Is that enough?
Tips and advice for a footing caster and fence builder are greatly appreciated.
(Edit: Maybe this should have been under earthworks & foundation...)
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Sounds like a strange instruction. But the hole should probably be 50 cm in diameter for the cellpast board to insulate well. But you should probably have 50 cm depth left after gravel and cellpast.
The hole should be 50 cm in diameter for the plinth to be drained. You fill gravel around the plinth, so water will not stand. Insulation is not entirely necessary, but normally one uses cellplast/frigolit. The easiest way is to cut out a circular piece and place it at the bottom.